1. Field of the Invention
This invention relates to methods and apparatus for launching a projectile. More specifically, this invention relates to methods and apparatus for facilitating launches of a projectile in the presence of a flowing medium.
While the present invention is described herein with reference to a particular embodiment, it is understood that the invention is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional embodiments within the scope thereof.
2. Description of the Related Art
As a result of motion of a submarine through water a submarine launched missile is exposed to a lateral hydrodynamic force as it emerges from the launch tube. This lateral hydrodynamic loading is proportional to the square of the forward velocity of the submarine and causes the missile to torque. Binding occurs between the partially exposed missile and the interior surfaces of the launch tube. Accordingly, submarines have been constrained to low forward velocities while launching missiles in order to reduce binding within the launch tube. Unfortunately, this phenomenon reduces the ability of a submarine to rapidly displace itself from a launch location in order to avoid detection.
Annular tube fillers have been utilized in an effort to minimize binding between the missile and launch tube. These tube fillers are inserted within the launch tube and serve to facilitate launch of the missile. Although the tube fillers reduce binding between the missile and launch tube precipitated by the torquing action of the flowing water, the submarine nonetheless remains constrained to travel at low velocities during missile launch. Moreover, annular tube fillers also reduce the maximum diameter of missiles which may launched from tubes in which such fillers are employed.
A similar binding occurs when missiles are launched from surface vessels. In particular, aerodynamic lateral forces (crossflow drag), arising from ship motion, torque missiles emerging from launch tubes which open into the crossflow. It follows that surface vessels are also typically limited to low forward velocities when launching missiles in a direction having a component normal to the direction in which the vessel is traveling. Moreover, surface winds of sufficient velocity in directions lateral to the intended initial path of the missile may also induce this undesired binding.
Accordingly, a need exists in the art for a method or apparatus for minimizing the lateral force exerted on missiles or other projectiles launched from vehicles in rapid motion within a fluid or gaseous environment.